# A question from the worksheet- superpostion

#### Yami

Joined Jan 18, 2016
279
A windmill-powered generator and a battery work together to supply DC power to a light bulb. Calculate the amount of current through each of these three components, given the values shown in the schematic diagram. Assume internal resistances of the generator and battery to be negligible: Ibatt = Ibulb = Igen =
I do not understand how to calculate the current through the battery and the generator. I do understand the bit about the light bulb ( calculating the current by 'short-circuiting' each source at a time).

#### MrAl

Joined Jun 17, 2014
7,591
Hello,

Short each source one at a time and calculate the response you want to know for each, then add the results.
That's called "superposition".

#### JoeJester

Joined Apr 26, 2005
4,259

#### Yami

Joined Jan 18, 2016
279
Yeah I do know about that but how to calculate the current through the source? The battery and the generator? Do the same as the light bulb, then whats the resistance of the battery and the generator?

#### Yami

Joined Jan 18, 2016
279
How I did for the light bulb, but when I try to do it for the sources I get ridiculous current values....

Ibatt = 3.992 A (charging) Ibulb = 3.013 A Igen = 7.006 A thats the answer for the question shown on the worksheet. why does the battery value state "charging"?

Last edited:

#### Yami

Joined Jan 18, 2016
279
Aah finally figured it out. Thanks for the help. Just final question though why does the battery have got "charging" stated?

#### JoeJester

Joined Apr 26, 2005
4,259
How I did for the light bulb, but when I try to do it for the sources I get ridiculous current values....
What did you get for the other currents?

Why would they be "ridiculous"?

On edit ...

What would the condition be if the battery were discharging and the condition of charging?

#### Yami

Joined Jan 18, 2016
279
What did you get for the other currents?

Why would they be "ridiculous"?

On edit ...

What would the condition be if the battery were discharging and the condition of charging?
Thats the part I don't get, condition when its charging and discharging

#### JoeJester

Joined Apr 26, 2005
4,259
In your superposition analysis, which device was supplying more current, the battery or the generator?